In "Dusk" by Saki discuss the events that lead Gortsby's thinking that he shouldn't be too clever in judging by circumstances. "Dusk" by Saki

Norman Gortsby is a rather cynical character who sits in
the "gloaming" hour on a bench in London's Hyde Park where others of fallen fortune and
hopes walk by.  As Gortsby, who has failed in some "subtle ambition" sits on alongside
an elderly gentleman; after the gentleman departs, out of the continuing dusk, a fairly
well dressed young man emerges, utters an angry word, and flings himself down onto the
bench. In reply to Gortsby's inquiry about his mood, the young man declares himself in a
"fix" because he has hurriedly left his hotel room in order to buy some soap, but cannot
recall neither which hotel it is or on which street it is located because the hotel at
which he had planned on staying has been torn down and replaced by a movie theatre. He
adds,

"Of
course I can wire to my people for the address, but they won't have my letter till
to-morrow; meantime I'm without any money...wandering about with twpence in my pocket
and nowhere to go for the
night."

Then, in response to
the young man who asks if Gortsby thinks he has simply fabricated his story, Gortsby
replies that the circumstances are not impossible since he has had a similar experience
in a foreign country. The young man responds to Gortsby's reminiscence about his similar
circumstances, hoping that Gotsby might yet have "the requisite decency" and give him
money for a hotel. But, says Gortby, the evidence that would have convinced him of the
veracity of the young man's tale is missing; namely, the bar of soap which the young man
supposedly set out to purchase.

With this remark, the young
man abruptly leaps to his feet exclaiming angrily, "I must have lost it," and he
departs, head held high.  Gortsby muses about the conversation, considering that the
detail of the story, the "convincing touch" was the soap.  When the young man could not
produce this soap, then his credibility was destroyed.  Ironically, however, Gortsby
happens to glance down as he starts to leave and discovers a bar of soap on the ground
where the young man had been sitting.  Guiltily, he hurries after the young man and
returns it to him, apologizing for his disbelief because appearances were against him. 
And, he gives the young man his card and a sovereign.  Blurting a word of thanks, the
young man "fled headlong in the direction of
Knightsbridge."

Returning to the bench, Gortsby chides
himself for being too quick to judge, believing himself clever.  Here, of course, is the
most telling irony of Saki's story since Gortsby was actually correct in his first
assessment of the young man's story because the soap belongs to the elderly gentleman
who returns to retrieve it.  Again, in the dusk Gortsby has "failed in a more subtle
ambition."